Surprised not to see any discussion of it here, so I thought I'd start something.

I cannot recall any other more disastrous incident in Japan since WW2. The images everywhere have been absolutely numbing. Aside from the thousands dead and missing, and the astonishing property damage, there's the looming risk of a nuclear catastrophe. "It's clear we are at Level 6, that's to say we're at a level in between what happened at Three Mile Island and Chernobyl," Andre-Claude Lacoste, president of France's nuclear safety authority, told reporters Tuesday. (So much for all the posters in energy debates around here who argued that nuclear is somehow a "clean" and viable alternative. )

The impact to Japan could have serious economic consequences on the rest of the world. It is the third largest economy in the world behind the US and China. (Aside -- Taiwan's govt tech PR firm is sending out message of support re- Japan; no question Computex in June -- and other tech trade events -- will be adverse affected.)

It's a natural disaster. No politics there. I think we expect the Japanese to be prepared and able to shoulder the burden of this disaster with minimal outside help and that whatever help they require will be given to them without reservations. No politics there either. So I don't think there's much to say other than condolences and good wishes which rarely make for a good argument.

We could argue about nuclear power but I'd rather not. Let's at least wait the dead are buried and the full impact of the nuclear incidents has been assessed. I'd also wait until the causes and contributing factors have been analyzed in some detail. I'd like to think no one would use a disaster like this as cheap fodder for political arguments (who am I kidding?).

I actually expect the net economic impact will be a positive in the same way that WWII was for many countries.

IMO the Japanese should have been better prepared for tsunamis striking the nuclear plants.If you look at the location of their nuclear plants, most of them are close to the sea:http://en.wikipedia.org/wiki/File:Japan ... ts_map.gifAnd apparently, they weren't designed / built to be tsunami-proof (as much as this can be achieved).Anyway, I wish them best of luck sorting this mess out.

PS. I am pro nuclear power, but I also want nuclear plants to be as safe as possible.

Not much detail on what's actually going on in the affected power plants. I get that:- the power for water cooling went out- the back up diesel generators failed (hard to stay running when your above-ground fuel tank is washed away)- lack of water flow caused steam pressure to rise /water level to drop and may have caused some water to disassociate into hydrogen and oxygen. - operators vented "steam" to lower containment pressure. - Free hydrogen in steam exploded. - and now they are pumping in saltwater + boron as a replacement for the lost water.

Here's the part I don't get. I thought nuke plants had a primary/secondary water cycle? Primary cycle in the containment vessel circulates water/steam. This goes thru a heat exchanger. Primary is cooled water and recirculated. The secondary then feeds the turbine. Primary water is radioactive. Secondary is not.

If they are feeding in boron to lower fuel rod activity....this implies the primary side...and NOT a closed cycle. eep.

All the experts in the articles I've read say the situation is much closer in severity to Three Mile Island than to Chernobyl.

You have to remember that these reactors are early 1970s technology, and are an early 1970s project in total. The many old reactors in service will always be a relative hazard and be objects of negative publicity. From what I understand, the newer designs are far less likely to melt down.

To be honest, I'm just happy that new reactors are being built. I hate the thought of burning coal.

There have been three explosions, and two fires. Two of the explosions were hydrogen explosions (in reactors #1 and #3) and they damaged only the outer/upper part of the buildings, and not the containment vessels. The third explosion (in reactor #2) was worse, and probably damaged the lower area below the containment vessel i.e. the ring where water circulates. The two fires were in the spent fuel storage pools in reactor #4, and are the cause of much of the radiation.

They are out of fuel in much of the area, and they are out of food in some areas. Water is apparently still available, sorta'. The towns and cities that were hit by the tsunami are pretty much wiped clean, with just matchsticks and concrete left behind.

All the experts in the articles I've read say the situation is much closer in severity to Three Mile Island than to Chernobyl.

Chernobyl did not have any kind of containment building/structure if a major problem occurred. They just figured it was too expensive and unlikely to be needed (obviously wrong). Nuclear plants in just about all other countries that I know of have such containment buildings/structures in case of a severe problem or even meltdown.

They do have to release some radioactive steam occasionally at the damaged plants in Japan (the steam is produced when they try to cool the reactor when normal cooling mechanisms have been damaged), but according the comments I saw from nuclear power plant experts, it is extremely unlikely that the containment structure would completely fail in Japan and would cause the kind of massive radiation contamination that occurred at Chernobyl (but I have no independent knowledge of whether that assessment is correct).

Here's the part I don't get. I thought nuke plants had a primary/secondary water cycle? Primary cycle in the containment vessel circulates water/steam. This goes thru a heat exchanger. Primary is cooled water and recirculated. The secondary then feeds the turbine. Primary water is radioactive. Secondary is not.

You're describing a PWR. The ones they tried to tame with boric acid following their emergency shutdown are BRWs which have a turbine subjected to radioactivity. There is something like a secondary to cool the condenser. It's a common design used in many countries.

CA_Steve wrote:

If they are feeding in boron to lower fuel rod activity....this implies the primary side...and NOT a closed cycle. eep.

What they did is not SOP of course. My understanding is that the cycle is usually closed but that the less dangerous reactors allow radioactive steam to be released if necessary during incidents.

The early analysis said this was similar to Three Mile Island. Now with the two fires, and the third explosion, which damaged the base of the reactor vessel #2 -- this has become much worse than TMI. They had to evacuate the last ~50 workers overnight, but they are back on site now, and they will continue to try to control things as best they can. This could get better as time goes on, but it seems much more likely that this will get worse. So, the potential to catastrophic failure similar to Chernobyl is still very possible -- but hopefully things fizzle before that happens.

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I was under the impression that it was very unlikely the containment structure would fail, even in the event of full melt down. I may have to eat my hat, though.

I have a hard time imagining a scenario where this will be "closer" to Chernobyl than TMI. Definitely bad, though!

At Chernobyl there was only one reactor that was breached. At Fukushima we have 6 to worry about (notice the spent fuel pools are an issue at all 6). I think we are already well past 3 Mile Island and the possibility of exceeding Chernobyl is not certain but is clearly a feasible at this point.

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At Chernobyl there was only one reactor that was breached. At Fukushima we have 6 to worry about (notice the spent fuel pools are an issue at all 6).

At Chernobyl a reactor *blew up*, apparently due to a nuclear explosion. Unless something unexpected happened recently, at Fukushima *no* reactors have sustained such an incident or such damage. The number of reactors affected by an incident in no way determines its seriousness and the radiation levels are totally different so far.

What's happening is obviously worse than TMI but Chernobyl is in a completely different league.

Please avoid lurid speculation. If you somehow have factual information about the risk of an explosion blowing away the containment or something, the post it. Otherwise it's irresponsible to spread baseless rumors with so many lives at stake.

At Chernobyl there was only one reactor that was breached. At Fukushima we have 6 to worry about (notice the spent fuel pools are an issue at all 6).

At Chernobyl a reactor *blew up*, apparently due to a nuclear explosion. Unless something unexpected happened recently, at Fukushima *no* reactors have sustained such an incident or such damage. The number of reactors affected by an incident in no way determines its seriousness and the radiation levels are totally different so far.

What's happening is obviously worse than TMI but Chernobyl is in a completely different league.

Please avoid lurid speculation. If you somehow have factual information about the risk of an explosion blowing away the containment or something, the post it. Otherwise it's irresponsible to spread baseless rumors with so many lives at stake.

Chernobyl may have had a small "Nuclear Explosion" but the majority of the problem even there was conventional explosions and fire.

The explosions and fire that have already happened at Fukushima are similar in nature to what happened at Chernobyl and the powers that be have already submitted a request to reclassify this ongoing event a level 7 (the same level as Chernobyl).

I'm not spreading baseless rumors. I'm stating facts. If you are confused by the terminology I can link to articles to explain them to you. For now I'll just quote a small portion to hopefully clear a little up for you.

Chernobyl wrote:

There was a sudden power output surge, and when an emergency shutdown was attempted, a more extreme spike in power output occurred, which led to a reactor vessel rupture and a series of explosions. This event exposed the graphite moderator components of the reactor to air, causing them to ignite. The resulting fire sent a plume of radioactive fallout into the atmosphere and over an extensive geographical area

Nuclear Explosion wrote:

A nuclear explosion occurs as a result of the rapid release of energy from an intentionally high-speed nuclear reaction. The driving reaction may be nuclear fission, nuclear fusion or a multistage cascading combination of the two.

Atmospheric nuclear explosions are associated with mushroom clouds, although mushroom clouds can occur with large chemical explosions, and it is possible to have an air-burst nuclear explosion without these clouds. Nuclear explosions produce radiation and radioactive debris.

Level 7 request wrote:

Google Translate's version:

Yamada Tetsurou WASHINGTON - U.S. civilian agencies, Institute for Science and International Security (ISIS) on April 15, Fukushima Daiichi nuclear power plant accident, the International Atomic Energy Agency (IAEA) established by the International Nuclear Event Scale (INES) 6 level presented the view that 7 or equivalent.

The institute "can no longer be viewed as a level four," he said. "Near the level 6, level 7 may reach" are trying to. In the past, nuclear accident, Chernobyl level seven former Soviet Union's worst, from the Three Mile Island accident was the U.S. level 5.

Yahoo's Babel Fish:

The American civil organization, the scientific international security laboratory (ISIS) announced opinion that in level it is suitable 6 or 7 with the international atomic energy phenomenon appraisal scale (INES) where the International Atomic Energy Agency (IAEA) decides on the 15th, concerning the accident of the Fukushima first nuclear plant. As for the same laboratory “it cannot already see as level 4,” that it points out. “To be close to level 6, perhaps, it reaches to level 7,” that it has done. In the past nuclear accident, the worst old Soviet in history & Chernobyl nuclear accident was level 7, as for American Three Mile Island nuclear accident level 5. (2011 March 16th 09:56 Yomiuri Shimbun Company)

Considering I already provided links to articles on The Oil Drum with plenty of documentation I thought you might actually try and read some of it before saying I'm making stuff up but if you want to be petty I won't be documenting every little detail for you in this thread. You will have to do some reading on your own or I'll just ignore your posts when I'm too busy to reply and educate you.

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Don't forget, that the spent fuel in the pools contains some plutonium, and there is a lot of fuel rods in those pools -- many more than in the reactor core. And there is virtually NO containment around them. The hydrogen explosions have blown holes in the building -- this is where they are going to attempt to shoot water with the water canon/fire truck. This is a pretty desperate move -- what else can they try? It is too radioactive to fly over with a helicopter...

The last two that we have not heard about -- reactor #5 and #6 also have spent rod pools, that may be less hot than #4, but they may well evaporate their water soon, and make matters much, much worse.

How hard was it previously to get water into those containment vessels.

Its hard to tell what is going on so far away, but it looks to like failed leadership, and leaders put in place for reasons other than ability to solve problems.

I suspect that much less harm to Japan, the Japanese people and world would have occurred if someone had gotten out their seppuku knife much earlier and removed themselves as a barrier to getting water into the containment vessel. It is probably a whole chain of inept Japanese good old boys whose criteria of advancement was what university they graduated from, how well they hold their Saki, how well they sing Karaoke.... oh... and how adept they are at telling superiors what they want to hear, instead of what is.

There is a world full a fire fighting helicopters that would have been available to them on request. Instead they were delivering three small loads of water per day. NO NO NO We have it under control. We don't need any help. Yeah Sure.... go get your seppuku knife under control. Mr. CEO, you fancy yourself as a Samurai, then act like one... but let your direct reports go first.

We don't know if the above is so.... but I am highly confident that when they investigate the response to the disaster, that is what they will find.

If they had electricity on site, then they could pump water in. Also, water has to circulated through the pools to cool the rods -- for years! Rods are used for about 6 years, and they need to be cooled on site for up to 10 years, before they can be put into dry storage.

These spent rod pools need to be cooled for longer than the rods produced power for.

There is very little news about the tsunami effects, and the basic needs of the people who were affected.

Considering I already provided links to articles on The Oil Drum with plenty of documentation

From one of the articles you linked:

Quote:

Comparisons are being made with the accident at Chernobyl, but there are a number of very important differences, notably in terms of reactor design, and therefore accident implications. Nuclear safety in the former Soviet Union was once my research field (see Nuclear Safety and International Governance: Russia and Eastern Europe), and the specifics of the accident at Chernobyl could not be replicated in Japan. The risk in Japan is primarily meltdown, not a Chernobyl-style run-away nuclear reaction.

RBMK (Reaktor bolshoy moshchnosty kanalny [high-power channel reactor]), Chernobyl-type reactors have a very large positive void coefficient, meaning that reactivity increases as a positive feedback loop. The presence of steam from overheating increases reactivity, which increases steam production. The graphite moderator in an RBMK is flammable, and RBMKs also have no containment system. If two or three of the 1700 channels in an RBMK are breached, the steam pressure will lift the lid, introducing air, while shearing the remaining tubes. Essentially, the reactor will explode on a sharp spike of reactivity. The moderator will catch fire, and a nuclear volcano will be the result. At Chernobyl, some 50 million Curies of radiation was released over several days.

Like the Fukushima incident, Chernobyl began with a loss of power, undertaken in that case as a test of safety systems commissioned long after the reactor became operational (the Chernobyl reactor had been in a state of critical vulnerability to blackout for two years at the time of the accident.) It could have been worse, however. Attempts to extinguish the fire at Chernobyl 4 came very close to causing a loss of power to the other three reactors at the site, which could easily have sent four reactors into into a critical state rather than one.

Edit: I'm not picking a fight, just saying we are not dealing with a nuclear explosion, and without one, containment should remain relatively in-tact.

There are some arguments for it, like the clean operation and the good power-to-size ratio of the plants. But there are cons and the biggest is simply the highly radioactive waste, that has to be contained for tens of thousands of years. And that is just insane and irresponsible.

But I think the current disaster is actually a good showcase for nuclear power (at least if you don't think of the waste containment issue). Among the destruction caused by earthquake and tsunami, the problems at the power plants seem small. The world is weirdly focused on them in the morbid expectation of another Chernobyl, when all experts tell them that it's not gonna happen. The security strategies seem to have held up very well.There's been a little bit of radioactivity released and this is bad - but Fukushima I (e.g.) has been operating since 1971: imagine all the environmental and health damages that three or four coal-power plants built instead would have caused over the last 40 years.

Klusu wrote:

Germany has shut down 7 plants. Strange... For how long?

Just for the record: it's a political play. Germany is largely Anti-Nuclear. When the Green Party was in the government, they put a law in motion that would have exited nuclear energy by 2030 or so. The current government promptly stopped this when they came to power. A lot of Germans were not happy. This thing in Japan has now refueled the anti-nuclear movement. There have been a few demonstrations against it already.The chancellor, whose government doesn't poll too well these days, is just trying to be pro-active about the situation. I'd expect the plants to remain down for just as long as this situation presists.

Unit 1 to right, reactor building destroyed by hydrogen gas explosion on Saturday 12th March. Unit 3, second from left, destroyed by hydrogen gas explosion on Monday 14th March, venting steam? Unit 2, second from right, explosion causes radiation leak from containment system, venting steam? Unit 4 on left, building destroyed by fire on Tuesday and Wednesday, the likely result of spent fuel rods boiling dry in their cooling pond. Ironically, it is unit 4, shut down at time of incident, with large quantities of radioactive material outside of containment, that is a major cause for concern.

More excerpts wrote:

On Monday 14th, the reactor building of unit 3 exploded in similar manner to unit 1 but, at this point, there was still no significant radiation leakage, and the containment vessel seemed to be doing its job. It became evident that the Japanese engineers were loosing the battle to keep the reactor cores submerged in water and adequately cooled.

On Tuesday 15th March a third explosion in unit 2 resulted in serious radiation leak. This was a game changing event since contamination of the site by radioactive materials created a much more hazardous operational environment and many of the staff, who seemed to be fighting a losing battle in any case, were evacuated.

The reactor building of unit 4 caught fire on Tuesday. Successfully extinguished, the building caught fire again on Wednesday 16th March and fears grew that spent fuel rods lying in a cooling pond outside of containment had boiled dry exposing the reactor site to large quantities of radiation. The photograph up top shows unit 4 to the left and it is clearly badly damaged even though the reactor was non-operational at the time of the incident.

Unit 3 is also reported to have spent fuel outside of containment that is giving rise to concern.

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They should have pretended like it was important and had generators staged outside the area to be flown in if necessary.

Even if they hadn't had the foresight to do that.... they should have mobilized $100 to $200 million in resources to get multiple generators from multiple places delivered to the the foot of the reactor..... Real simple, the Prime minister of Japan calls up the CEOs of the handful of companies that make large portable industrial generators... gets the identities of companies in Japan who own them. Then calls their CEOs obtains from them permission for the Japanese armed forces to go get those generators and try to rush them to the reactors.

Then do something similar for firefighting helicopters. And something similar for floating water pumpers. And something similar for water pumpers on wheels.

There is a lot of information missing right now, but there is ample evidence that they didn't even try. Shame on them. Shame Shame Shame.

It's easier to imagine that it was the incredible devastation that has prevented them from restoring electricity on site. While it's been mentioned that the Japanese central government is relatively weak, and that it can be pictured that corporations there have a more assumed/expected paternalistic responsibility (whether realistic or not); still, if the problem could have been solved days ago by bringing in generators then you'd think it would have been done.

They should have pretended like it was important and had generators staged outside the area to be flown in if necessary.

Flown in how, exactly? Have you ever seen these things? They come in a double-standard-sized container on the back of a 40-tonne truck. They get off-loaded by a massive ****-off crane, also on the back of a 40-tonne truck.

Had it occurred to you that maybe, just maybe, they weigh more than a helicopter can lift?!

Bad place specifically for a Boiling Water Reactor (BWR). Japan likes the BWR design but they do have an inherently more dangerous primary coolant loop than a Pressurised Water Reactor (PWR) as you run the primary coolant through the turbines themselves. The secondary coolant is the seawater the other side of the condensor. In a PWR the primary coolant goes througha heat exchanger and this causes the secondary coolant to boil which drives the turbines and then a tirtiary coolant (normally seawater) is on the other side of the condensor.

If this was a PWR then a failed set of generators would be a non-issue.

A BWR is certainly NOT as bad as the RBMK (reaktor bolshoy moshchnosti kanalniy) design at Chenobyl, a reactor design so bad that the inventor didn't want it to be used and was sent to Siberia to shut him up. It was also a boiling water reactor however was only dangerous because of its positive power coeffiecent below 40% power and most importantly, its positive void coefficient!

I used to be a nuclear engineer and it is a very safety driven industry. Japan doesn't have the best safety record if you look back historically.

In the big scheme of things, the danger of the reactors is nothing like the severity of the tsunami itself. To put things in perspective Chenobyl may cause up to 4000 cancer deaths and Three Mile Island 2/3 (two thirds of a death, the IAEA estimate) but the tsunami itself has significantly surpassed that.

I do not think this can be another Chenobyl. Looking at the INES scale (http://en.wikipedia.org/wiki/Internatio ... vent_Scale) this may well be somewhere between Three Mile Island, 1957 Windscale fire (much worse than TMI )and Kyshtym, an accident little is known about.

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